Field of the Invention
The present invention relates to a method of producing a fuel cell stack including a membrane electrode assembly and a metal separator. The membrane electrode assembly includes a pair of electrodes and an electrolyte membrane interposed between the electrodes. Further, the present invention relates to a method of producing a metal separator for a fuel cell.
Description of the Related Art
For example, a solid polymer electrolyte fuel cell includes a membrane electrode assembly (MEA) having an electrolyte membrane. The electrolyte membrane is a polymer ion exchange membrane. An anode is provided on one surface of the electrolyte membrane, and a cathode is provided on the other surface of the electrolyte membrane. The membrane electrode assembly is sandwiched between separators (bipolar plates) to form a power generation cell. Normally, a predetermined number of the power generation cells are stacked together to form a fuel cell stack. For example, the fuel cell stack is mounted in a fuel cell vehicle (fuel cell electric automobile, etc.) as an in-vehicle fuel cell stack.
In some cases, the fuel cell may adopt metal separators as the separators. In this regard, seal members are provided on the metal separators for preventing leakage of reactant gas such as an oxygen-containing gas and a fuel gas, and a coolant. Seals made of elastic rubber such as fluoro-rubber, silicone-rubber, or the like are used as the seal members. Use of such seal members push up the cost disadvantageously.
To this end, for example, as disclosed in the specification of the U.S. Pat. No. 6,605,380, it has been proposed to adopt a structure where sealing beads are formed on the metal separators instead of the elastic rubber seals. Since the sealing beads are fabricated by press forming, the product cost can be suppressed advantageously.